The modern pneumatic tire for vehicles is a composite of elastomeric material reinforced with fibrous elements in the form of cords of textile, wire or glass materials. The construction of such a tire requires a plurality of manipulative steps and a number of materials of diverse natures, which necessitate large capital investments for sophisticated equipment and a substantial number of operator-guided manipulations. Hence, in spite of their comparatively low cost, modern pneumatic tires for vehicles can be considered both labor and capital intensive.
Efforts to reduce the cost of tires have generally taken the form of increasing complexity of machinery in an effort to reduce the amount of high cost labor required. While significant improvements have been achieved by these expedients, the modern manufacture of a vehicle tire still reqiures the procurement, preparation and incorporation into the product of a large number of diverse materials with resulting complexity and high cost of the apparatus for utilizing those materials.
Some efforts have been made to form tires without filamentary reinforcements, as for example, by casting or molding tires from polyurethane and similar materials. While such tires do eliminate the need for many of the materials customarily employed in conventional rubber-fabric construction, other difficulties have arisen which have thus far prevented adoption of tires of this nature, except for a few special uses.